// See License comments in shader string

(function(Blotter, _) {

  Blotter.Assets.Shaders.Noise4D = [
    "//",
    "// Description : Array and textureless GLSL 2D/3D/4D simplex",
    "//               noise functions.",
    "//      Author : Ian McEwan, Ashima Arts.",
    "//  Maintainer : ijm",
    "//     Lastmod : 20110822 (ijm)",
    "//     License : Copyright (C) 2011 Ashima Arts. All rights reserved.",
    "//               Distributed under the MIT License. See LICENSE file.",
    "//               https://github.com/ashima/webgl-noise",
    "//",
    "",
    "vec4 mod289(vec4 x) {",
    "  return x - floor(x * (1.0 / 289.0)) * 289.0; }",
    "",
    "float mod289(float x) {",
    "  return x - floor(x * (1.0 / 289.0)) * 289.0; }",
    "",
    "vec4 permute(vec4 x) {",
    "     return mod289(((x*34.0)+1.0)*x);",
    "}",
    "",
    "float permute(float x) {",
    "     return mod289(((x*34.0)+1.0)*x);",
    "}",
    "",
    "vec4 taylorInvSqrt(vec4 r)",
    "{",
    "  return 1.79284291400159 - 0.85373472095314 * r;",
    "}",
    "",
    "float taylorInvSqrt(float r)",
    "{",
    "  return 1.79284291400159 - 0.85373472095314 * r;",
    "}",
    "",
    "vec4 grad4(float j, vec4 ip)",
    "  {",
    "  const vec4 ones = vec4(1.0, 1.0, 1.0, -1.0);",
    "  vec4 p,s;",
    "",
    "  p.xyz = floor( fract (vec3(j) * ip.xyz) * 7.0) * ip.z - 1.0;",
    "  p.w = 1.5 - dot(abs(p.xyz), ones.xyz);",
    "  s = vec4(lessThan(p, vec4(0.0)));",
    "  p.xyz = p.xyz + (s.xyz*2.0 - 1.0) * s.www;",
    "",
    "  return p;",
    "  }",
    "",
    "// (sqrt(5) - 1)/4 = F4, used once below",
    "#define F4 0.309016994374947451",
    "",
    "float snoise(vec4 v)",
    "  {",
    "  const vec4  C = vec4( 0.138196601125011,  // (5 - sqrt(5))/20  G4",
    "                        0.276393202250021,  // 2 * G4",
    "                        0.414589803375032,  // 3 * G4",
    "                       -0.447213595499958); // -1 + 4 * G4",
    "",
    "// First corner",
    "  vec4 i  = floor(v + dot(v, vec4(F4)) );",
    "  vec4 x0 = v -   i + dot(i, C.xxxx);",
    "",
    "// Other corners",
    "",
    "// Rank sorting originally contributed by Bill Licea-Kane, AMD (formerly ATI)",
    "  vec4 i0;",
    "  vec3 isX = step( x0.yzw, x0.xxx );",
    "  vec3 isYZ = step( x0.zww, x0.yyz );",
    "//  i0.x = dot( isX, vec3( 1.0 ) );",
    "  i0.x = isX.x + isX.y + isX.z;",
    "  i0.yzw = 1.0 - isX;",
    "//  i0.y += dot( isYZ.xy, vec2( 1.0 ) );",
    "  i0.y += isYZ.x + isYZ.y;",
    "  i0.zw += 1.0 - isYZ.xy;",
    "  i0.z += isYZ.z;",
    "  i0.w += 1.0 - isYZ.z;",
    "",
    "  // i0 now contains the unique values 0,1,2,3 in each channel",
    "  vec4 i3 = clamp( i0, 0.0, 1.0 );",
    "  vec4 i2 = clamp( i0-1.0, 0.0, 1.0 );",
    "  vec4 i1 = clamp( i0-2.0, 0.0, 1.0 );",
    "",
    "  //  x0 = x0 - 0.0 + 0.0 * C.xxxx",
    "  //  x1 = x0 - i1  + 1.0 * C.xxxx",
    "  //  x2 = x0 - i2  + 2.0 * C.xxxx",
    "  //  x3 = x0 - i3  + 3.0 * C.xxxx",
    "  //  x4 = x0 - 1.0 + 4.0 * C.xxxx",
    "  vec4 x1 = x0 - i1 + C.xxxx;",
    "  vec4 x2 = x0 - i2 + C.yyyy;",
    "  vec4 x3 = x0 - i3 + C.zzzz;",
    "  vec4 x4 = x0 + C.wwww;",
    "",
    "// Permutations",
    "  i = mod289(i);",
    "  float j0 = permute( permute( permute( permute(i.w) + i.z) + i.y) + i.x);",
    "  vec4 j1 = permute( permute( permute( permute (",
    "             i.w + vec4(i1.w, i2.w, i3.w, 1.0 ))",
    "           + i.z + vec4(i1.z, i2.z, i3.z, 1.0 ))",
    "           + i.y + vec4(i1.y, i2.y, i3.y, 1.0 ))",
    "           + i.x + vec4(i1.x, i2.x, i3.x, 1.0 ));",
    "",
    "// Gradients: 7x7x6 points over a cube, mapped onto a 4-cross polytope",
    "// 7*7*6 = 294, which is close to the ring size 17*17 = 289.",
    "  vec4 ip = vec4(1.0/294.0, 1.0/49.0, 1.0/7.0, 0.0) ;",
    "",
    "  vec4 p0 = grad4(j0,   ip);",
    "  vec4 p1 = grad4(j1.x, ip);",
    "  vec4 p2 = grad4(j1.y, ip);",
    "  vec4 p3 = grad4(j1.z, ip);",
    "  vec4 p4 = grad4(j1.w, ip);",
    "",
    "// Normalise gradients",
    "  vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));",
    "  p0 *= norm.x;",
    "  p1 *= norm.y;",
    "  p2 *= norm.z;",
    "  p3 *= norm.w;",
    "  p4 *= taylorInvSqrt(dot(p4,p4));",
    "",
    "// Mix contributions from the five corners",
    "  vec3 m0 = max(0.6 - vec3(dot(x0,x0), dot(x1,x1), dot(x2,x2)), 0.0);",
    "  vec2 m1 = max(0.6 - vec2(dot(x3,x3), dot(x4,x4)            ), 0.0);",
    "  m0 = m0 * m0;",
    "  m1 = m1 * m1;",
    "  return 49.0 * ( dot(m0*m0, vec3( dot( p0, x0 ), dot( p1, x1 ), dot( p2, x2 )))",
    "               + dot(m1*m1, vec2( dot( p3, x3 ), dot( p4, x4 ) ) ) ) ;",
    "",
    "  }"
  ].join("\n");

})(
  this.Blotter, this._
);
